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# lighting ??

#1
08-24-01, 04:54 AM
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Hello,
Can someone please tell me what would be the proper formula to use to figure out how many recessed lights can be placed on one curcuit. Is 12/2 wire good for this install?

Thanks
Slick

#2
08-24-01, 06:43 AM
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Join Date: Sep 2000
Location: United States
Posts: 18,497
Assumptions:[list=1][*]20-amp circuit.[*]Nothing but the lighting on the circuit.[*]65-watt type R bulbs.[/list=1]
20 amps tims 120 volts = 2400 watts.
2400 watts divided by 65 watts = 36 fixtures

For an extra margin of safety, use 80% of the available 2400 watts.

2400 watts times 80% = 1920 watts
1920 watts divided by 65 watts = 29 fixtures

If your situation is different than my assumptions, then substitute your own numbers in the calculations above.

12/2 is perfect!

#3
08-24-01, 07:29 AM
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Hello John Nelson,
Thank you very very much for that important tool. I'm sure someone else on this board would like to know this formula as well.
Thanks Again Slick

#4
08-24-01, 07:32 AM
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John,
How do you figure out for recepticles?
Thanks
Slick

#5
08-24-01, 08:19 AM
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Join Date: Sep 2000
Location: United States
Posts: 18,497
Receptacles aren't so clear-cut, since nobody knows what you might plug into a receptacle.

It's standard practice, but by no means required, to assume that somewhere around 1.5 amps (i.e., 180 watts) will be used at each receptacle. This, of course, varies all over the place from house to house, depending on the lifestyle of the occupants.

Most people hold that receptacle-only circuits should have no more than 8 duplex receptacles on a 15-amp circuit, and 10 on a 20-amp circuit. But you are free to violate this guideline in either direction if you know something about the intended usage of these receptacles.

The applicable code requirement is to have at least one general-purpose 15-amp circuit per 600 square feet of living space, or at least one general-purpose 20-amp circuit per 800 square feet of living space.

#6
08-25-01, 11:59 AM
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Right on John..... 220-3(b)(4) & (10)

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